Ch 3 Manufacturing Models and Metrics Sections 1

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Ch 3 Manufacturing Models and Metrics Sections: 1. Mathematical Models of Production Performance 2.

Ch 3 Manufacturing Models and Metrics Sections: 1. Mathematical Models of Production Performance 2. Manufacturing Costs © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 1

Production Concepts and Mathematical Models § § § Production rate Rp Production capacity PC

Production Concepts and Mathematical Models § § § Production rate Rp Production capacity PC Utilization U Availability A Manufacturing lead time MLT Work-in-progress WIP © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 2

Operation Cycle Time Typical cycle time for a production operation: Tc = To +

Operation Cycle Time Typical cycle time for a production operation: Tc = To + Th + Tth where Tc = cycle time, To = processing time for the operation, Th = handling time (e. g. , loading and unloading the production machine), and Tth = tool handling time (e. g. , time to change tools) © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 3

Production Rate Batch production: batch time Tb = Tsu + QTc Average production time

Production Rate Batch production: batch time Tb = Tsu + QTc Average production time per work unit Tp = Tb/Q Production rate Rp = 1/Tp Job shop production: For Q = 1, Tp = Tsu + Tc For quantity high production: Rp = Rc = 60/Tp since Tsu/Q 0 For flow line production Tc = Tr + Max To and Rc = 60/Tc © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 4

Production Capacity Plant capacity for facility in which parts are made in one operation

Production Capacity Plant capacity for facility in which parts are made in one operation (no = 1): PCw = n Sw Hs Rp where PCw = weekly plant capacity, units/wk Plant capacity for facility in which parts require multiple operations (no > 1): PCw = where no = number of operations in the routing © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 5

Utilization and Availability Utilization: U = where Q = quantity actually produced, and PC

Utilization and Availability Utilization: U = where Q = quantity actually produced, and PC = plant capacity Availability: A = where MTBF = mean time between failures, and MTTR = mean time to repair © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 6

Availability MTBF and MTTR Defined © 2008 Pearson Education, Inc. , Upper Saddle River,

Availability MTBF and MTTR Defined © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 7

Manufacturing Lead Time MLT = no (Tsu + QTc + Tno) where MLT =

Manufacturing Lead Time MLT = no (Tsu + QTc + Tno) where MLT = manufacturing lead time, no = number of operations, Tsu = setup time, Q = batch quantity, Tc = cycle time per part, and Tno = non-operation time © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 8

Work-In-Process WIP = where WIP = work-in-process, pc; A = availability, U = utilization,

Work-In-Process WIP = where WIP = work-in-process, pc; A = availability, U = utilization, PC = plant capacity, pc/wk; MLT = manufacturing lead time, hr; Sw = shifts per week, Hsh = hours per shift, hr/shift © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 9

Costs of Manufacturing Operations § Two major categories of manufacturing costs: 1. Fixed costs

Costs of Manufacturing Operations § Two major categories of manufacturing costs: 1. Fixed costs - remain constant for any output level 2. Variable costs - vary in proportion to production output level § Adding fixed and variable costs TC = FC + VC(Q) where TC = total costs, FC = fixed costs (e. g. , building, equipment, taxes), VC = variable costs (e. g. , labor, materials, utilities), Q = output level. © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 10

Fixed and Variable Costs © 2008 Pearson Education, Inc. , Upper Saddle River, NJ.

Fixed and Variable Costs © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 11

Manufacturing Costs § Alternative classification of manufacturing costs: 1. Direct labor - wages and

Manufacturing Costs § Alternative classification of manufacturing costs: 1. Direct labor - wages and benefits paid to workers 2. Materials - costs of raw materials 3. Overhead - all of the other expenses associated with running the manufacturing firm § Factory overhead § Corporate overhead © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 12

Typical Manufacturing Costs © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All

Typical Manufacturing Costs © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 13

Overhead Rates Factory overhead rate: FOHR = Corporate overhead rate: COHR = where DLC

Overhead Rates Factory overhead rate: FOHR = Corporate overhead rate: COHR = where DLC = direct labor costs © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 14

Cost of Equipment Usage Hourly cost of worker-machine system: Co = CL(1 + FOHRL)

Cost of Equipment Usage Hourly cost of worker-machine system: Co = CL(1 + FOHRL) + Cm(1 + FOHRm) where Co = hourly rate, $/hr; CL = labor rate, $/hr; FOHRL = labor factory overhead rate, Cm = machine rate, $/hr; FOHRm = machine factory overhead rate © 2008 Pearson Education, Inc. , Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 15